In response to a need for a package with a reclosable opening, U.S. Pat. No. 3,104,591 (Ahlbor) describes a soft package for cigarettes or similar articles, which is designed to combine certain advantages of both a soft package and a rigid box. The body of the package is made of a thin wrapper or envelope blank. The soft package has a rectangular top end, which includes an adhesively attached cap made from a cap blank consisting of a more rigid material than the thin wrapper which forms the package body. According to the patent, the cap blank has incisions to form a lid opening when the cap is attached to the package body, and includes a fold line along the top of the opening that provides a hinged lid. The cap blank is secured, via adhesive zones, to the top end of the package so as to form a cap over half of the top end. The package body beneath the attached cap is perforated with tearing lines that allow the portion of the wrapper attached beneath the lid opening to be torn away and swung upwardly with the lid when it is opened. Although this patent recognized the need for a package with a reclosable opening, a need for a rigid container with a reclosable locking feature that was at the same time suitable for packaging delicate materials, such as flaky foods, remained evident in the art.
Rigid, reclosable paperboard containers suitable for packaging dry materials have more recently been developed for packaging food materials. For example, U.S. Pat. Nos. 3,765,593, 4,421,236, 4,768,703 and 5,911,359 disclose box containers having reclosable openings. U.S. Pat. No. 3,765,593 (D'Alessio) discloses a tubular cardboard carton having a diagonal flip-top structure that is formed from a single panel blank. The blank is cut and folded to form a front panel having a cutaway edge that is recessed from the edge of the upper end of the box, thereby forming an opening, and a rear panel having an extended tab portion contiguous with its side edge. When the panels are folded to form the carton, the extended tab portion of the rear panel folds over the edge of the opening in the front panel to form an integral side-hinged closure that covers the opening. This type of closure, however, cannot be locked to secure the opening and prevent spillage of the contents from the container, if, for example, the carton is inverted.
U.S. Pat. No. 4,421,236 (Lowe) discloses a carton for packaging cereals or other dry products, which is constructed from a blank having side and end closure flaps that are extensions of the front, rear and end panels of the blank. The reclosable opening is formed by imparting tear lines in a parallel spaced relationship to the upper edges of the front, rear and end panels, score lines in parallel spaced relationship to the tear lines, die cuts at the ends of each tear line, and further having a score line across the top portion, the combination of which integrally forms an upwardly pivotable flap. When the sealed carton is opened along the tear lines and folded back along the score line, the flap forms a pouring spout for dispensing of product from the carton. Lowe provides that the carton may also include a barrier coating or laminate that eliminates the need for a separate liner, and which maintains the freshness or integrity of the product stored in the carton. The disclosed closure means cannot be secured. Additionally, Lowe does not disclose or contemplate maintaining the integrity of the barrier coating or laminate in the unopened carton, since the tear lines in such cartons typically penetrate and therefore compromise the barrier coating or laminate material.
U.S. Pat. No. 4,768,703 (Sosler) discloses a carton having a top cover with a peripherally depending flange that is affixed to the open top end of the carton. Perforation lines around the periphery of the flange that penetrate through the flange as well as the front, rear and end panels of the carton, and a transverse score line in the top panel form a reclosable hinged cover and pour spout. The pour spout is closed by pulling the hinged cover downward over the open top end of the carton. A membrane liner may be separately heat sealed to the open top end of the carton before the top cover is attached. In this regard, after the carton is opened, the membrane liner portion may be pivoted upwardly and outwardly to dispense the carton contents, and the carton may be reclosed by pushing the membrane liner downward over the open top end then closing the hinged cover. Once the carton is opened by tearing along the perforations, it may be locked in open position by orienting the perforations in the flange so that they extend angularly from the opposing edges of the top panel to terminal flange edges in the unopened section of the cover. This closure means is not secure, however, and is susceptible to inadvertent opening and spillage of the carton contents if, for example, the carton is inverted. Moreover, the membrane liner does not provide full barrier protection to the package contents when it is unopened, since the inside of the carton is not completely sealed.
U.S. Pat. No. 5,911,359 (Stone) discloses a one-piece, flip-top carton with a lid formed from the combination of a perforation oriented parallel to the top edge of one end panel, obliquely oriented perforations along the front and rear panels, and at least one horizontal fold line across the closed top end. The carton blank is shaped to include a tabbed portion that, when folded, forms the flip top. This type of closure does not provide secure fastening means. The patent neither mentions nor suggests a means of dealing with the problem of deterioration of the package contents due to exposure to air and moisture.
None of the foregoing references addresses the problem of protecting the contents of the sealed container from exposure to light, oxygen or moisture vapor before it is opened. Other patents, however, have attempted to provide such barrier packaging. U.S. Pat. No. 4,239,150 (Schadowski) discloses a folding carton for leak-proof packaging of liquids having a skived side seam formed by shaving one side of the seam to form a tapered wedge. The wedge is then overlapped beneath the thicker, untapered portion of the seam to form a joint that is then bonded or sealed. The patent mentions that the seam so formed provides high liquid tightness even when the lapped seam is of slight thickness. The carton disclosed by this patent does not include any features to provide hermetic barrier packaging of materials while providing ease of opening, and no mention is made of a reclosable closure.
U.S. Pat. No. 5,101,999 (Robichaud) discloses a closure mechanism for cartons used in liquid packaging, the closure having a base attachable to the top of the carton over a scored area consisting of a first and second perimeter cut, each of which may be serrated or perforated, to permit penetration of an outer polyethylene layer; and a series of half cuts and arc cuts circumscribing a middle cut, which are designed to produce “bomb bay” doors when the middle cut is depressed inward by a push-tab or button appended from the inside of the hinged lid of the closure mechanism. The carton may preferably be formed from a laminate having therein a barrier material that is maintained unbroken in advance of opening. The disadvantage of the disclosed closure means is that it does not permit easy opening, as considerable pressure must be exerted on the push-tab to puncture the middle cut and form the “bomb bay” doors, and the scored area forming the opening is not maintained external to the carton. Rather, the broken scored area is pushed inward and therefore it cannot be removed from the carton after it is opened. The carton opening so formed is not a completely unobstructed opening, and, as a result, this type of closure cannot efficiently be used to package a pourable non-liquid material.
Most recently, the need for an easy to open barrier carton suitable for packaging non-liquid materials was addressed by U.S. Pat. No. 6,047,883 (Calvert). Calvert describes a bagless barrier paperboard container having a locking, reclosable fitment closure affixed to the top panel in parallel relation to the front and rear panels. The inner contact surface of the container is coated with a polymeric coating that exhibits excellent moisture vapor, oxygen and flavor barrier characteristics. A disadvantage of the Calvert container, however, is that in order to provide easy opening, a peelable sealant closure must be applied to the top fin or gable seal to form an opening means, and the inclusion of this element may compromise the barrier properties.
Accordingly, there is a need evident in the art for a fairly rigid, product-protecting packaging container that can be manufactured with a locking, reclosable fitment or closure means for securing the container opening, whether such closure means is in an open or closed position, while providing excellent barrier properties prior to opening of the container.